Quick reversing motor



Jan. 23, 1945. w. w. 'WARNER 2,367,982

'QUICK REVERSING MOTOR Filed March 9, 1944 2 Sheets-Sheet 1 4 Inventor-zWilbur" W; Warner, y 1/ 4) His ttor neg.

jan. 23, 1945.

w. w. WARNER u ck REVERSING MOTOR Filed March 9, 1944 2 Sheets-Sheet 2REGENERATIVE BRAKING mm w hE wm ml- C MAIN FIELD REVERSED um? CLOSEPLUGGING CLOCKWISE START/N6 AND RUNNING Wilbur \Mwarner', by WW5) E HisAttorney.

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Wilbur W. Warner, Fort Wayne, 11ml, assignor to General ElectricCompany, a corporation oi? New York i Claims.

My invention relates to quick reversing capacitor, split-phase,alternating current motors us= ing dynamic braking during a reversingoperation. and an important object of my invention is to provide manualswitching apparatus which will perform the necessary switchingoperations in proper sequence without the aid of relays. This isaccomplished by using coordinated switches, preferably of the snap orquick actin type.

The features or my invention which are be lieved to be novel andpatentable will be pointed out in the claims appended hereto. For a.better understanding of my invention, reference is made in the followingdescription to the accompanying drawings in which Fig. 1 illustrates acapacitor motor connected for operation through double throw snap actionswitches, the switches bein shown in motor running positions for onedirec= tion of rotation; Fig. 2 represents the switches in line open,regenerative braking circuit condition; Fig. 3 represents the conditionof Fig. 2, except with the main field reversed; and Fig. 4 representsthe switch condition for the opposite direction or motor operation.

Referring to Fig. i, it represents the squirrelcage rotor of asplit-phase capacitor start motor having the quadrature displaced statormain winding it and start winding it. A capacitor 1 i3 is included inthe starting winding circuit which circuit is arranged to be opened byan automatic switch it, represented as the type operated by acentrifugal device it driven by the motor. as the motor comes up tospeed. The

source of single alternating current supply tor the motor is app ied toline terminals 5 and I1, line terminal is being connected directly toone end of the start winding it and to the stationary blades l9 and 23cooperate with upper contacts is and 26 respectively on the right, whichare.

connected to opposite ends oi the main winding for one direction oienernisation, and these same switch blades cooperate with lower contacts21 and 28, respectively, on the right, also connected to opposite endsor the main winding ior enerend of the main winding.

The switch blade iii has parallel connected upper and lower stationarycontacts 29 on the right, and when in the lower position shown in Fig. 1serves as a line switch with respect to supply line ill for the mainwinding H, and when the centrifugal speed responsive switch it isclosed, for the start winding l2 also. When switch blade 20 is in thedonor position, it con nects upper contact 29 with the ripper left contact 38 to establish a series connection oi the start and main windingsthrough condenser 13 for dynamic braking purposes. This connection isindependent of the speed responsive switch it. Switch blade it is alsomounted on a push rod 8i, and the push rods 22 and it are biasedupwardly against earns 32 and at by springs 34 andBE compressed betweenstationary abutments and projections on the push rods. Each of theswitch blades has a pair oi resilient fingers 38 extending toward thepush rods from opposite sides, and these are nlvotaliy engorged inrecesses contacts l8 oi the lower right-hand switch having the snapaction blade iii. The line terminal it connects to the lower stationarycontact 20 of the left-hand switch having the snapaction blade it.Mounted on the push rod 22 .with the previously mentioned switch bladeI9 is a third snap action switch blade at, and, since the blades 99 and'23 are mounted on the some push rod 22.

these switches are operoted substantially simul taneously. The switchblades it and and the stationary contacts associated therewith comprisethe reversing switch for the main winding l l. The upper blade 23cooperates with stationary contacts it on the left through whichconnection is made to the main winding II from line terminal II throughthe switch blade 2|, when the latter is in the lower position shown.Switch formed byloent strap memhers 3i secured to the push rods. Theconstruction cleerly shown in the drawings is such as to iorm a snapaction toggle tor the switch blades which have resilient connecting sidesections 3% on either side of the push rods. lll'ius when the push rodit. Fig.4, is moved downward, the lingers cc oi switch 2| are moveddownward under compression forces past dead center. whereupon the switchsnaps from the lower contacts to the upper contacts substantiallyinstantaneously.

The cams i2 and 33 are mounted on a common shaft 39 so as to be turnedsimultaneously, and.

the surfaces of the cams are so shaped as to perform the several switchoperations in a desired sequence as the shait is turned. by any suitableoperating means represented by the operating handle to. There are tourdiilerent operating positions for the com operated switch mechanism. oneof which is shown in Fig. 1, and others of which are shown in Figs. 2,3, and 4. In the letter figures the lower switch it hos tween omit ted.

It is evident from the connections shown in Fig. i that the motor isconnected tor "up to speed" single-phase operation on the main windingalone, and for purposes of explanation this will be assumed as thecounterclockwise running position of the switch mechanism. To reversethe motor, cam shaft 39 is turned cloclrwise from the position shown inFig. 1 first to the position shown in Fig. 2. In the position of Fig. 2the main winding reversing switch remains unchanged but switch 2! hasmoved to the upper contacts to open the line connection and to establish a braking circuit where the main and start windings aredisconnected from line ii and connected in series with the condenser it.This causes quick dynamic braking deceleration of the motor, allowingthe speed responsive switch I to close. A further movement oi com shalt359 in the clockwise direction (routes the znoin ileld winding ii to hereversed by reason oi. switches ill and 23 moving to the lower contactswhich is the switch position represented in Fig. 3. Further movement ofcam shaft 39 in the clockwise (llIEG-r tion produces the clockwisestarting condition represented in Fig. 4, where the switch M has movedto the lower contacts to interrupt the dynamic braking circuit andconnect the motor to line H: The switch ll now being closed, the motorstarts in the clockwise direction and comes up to speed during whichtime the centrifugal switch It opens and the motor then runssingle-phase in the clockwise direction.

I have found that the usual capacitor motor will produce what is heretermed dynamic braking regardless of the direction of rotation relativeto the direction in which the main field winding is connected and if inmoving from the switch position of Fig. 1 to the switch position of Fig.3 the movement is made quickly, dynamic braking will occur although themain field winding is reversed in the meantime, and dynamic braking willcontinue after the motor speed has been reduced below the point wherethe speed responsive switch I closes. Hence, it is relatively immaterialwhether the operator switches quickly or relatively slowly from thecondition of Fig. 1 to that of Fig. 3 in order to obtain dynamicbraking. Also, as soon as the speed responsive switch closes duringdeceleration, the motor may be plugged by moving the switching mechanismfrom the position of Fig. 3 to that of Fig. 4 before the motor has cometo rest. The reversing of the motor from clockwise operation tocounter-clockwise operation proceeds in the same manner by simplyreversing the direction of rotation of the cam shaft SI. It is importantto the operation that a reversing switch be used which cannot stay inopen position but is closed in one or the other direction for everyposition of the operating cams.

, It will be noted that when the raised portion of the cam 33 isopposite push rod II, the motor line circuit at contact Ill is open andanytime it is desired tostop the motor without reversing, the switchmechanism may be left in such "line open" condition. The motor may thenbe started in either direction of rotation, clockwise by rotating thecam shaft clockwise, and counterclockwise by rotating the cam shaftcounterclockwise.

If desired. stops I l may be provided as shown in Fig. 1 to limit themovement of the cam shaft 7 to the range of operation herein described.

It is seen from the foregoing description that the switch operatingcoordinating cam arrangepositions the other switch ill so as to connectthe motor to its source oicupply during the let and 4th range portionsand connects the motor windings in series with the condenserindependently of the speed responsive witch during the 2nd and 3rd rangeportions. .i'his interlocked overlapping operating arrangement oiswitches results in the tour switch operctiiur conditions described.

The same switch m chanism may need i out the dynamic lore r; denture icydiscount the connection 42 or using to motor 't not develop dynamicnotion ample the resistance tionel capacity for star our purposes rcluded in the starting winding clrcui, :li desired. 7

when the control is used for overhead crane operation controlled fromthe floor, the switch may also bemountcd overhead and operated by ropestied into the openings shown in the two ends of the handle 40. Thedetails or the swiinhes and coordinated operating means may be varied usconditions require.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is;

1. A split-phase motor having quadrature displaced main and startwindings, a condenser in series with the start winding, means responsiveto the speed of the motor for opening and closin the starting windingcircuit as the motor comes up to and deceleratcs from running or respectively, a source of single-phase supply r the motor, a snap actionreversing switch the main winding, another snap action switch having oneposition for connecting the motor to its source of supply and anotherposition where said connection is interrupted and the main and startwindings are connected in series with the condenser through thereversing switch and independently of the speed responsive means forestablishing a dynamic braking circuit, and common operating means forsaid switches movable in opposite directions over an operating rangedivided into 1st, 2nd, 3rd, and 4th consecutive portions, said meanspositioning the reversing switch for one direction of motor operationover the 1st and 2nd range portions and for the op- DOBite direction ofrotation over the 3rd and 4th range portions, and positioning said otherswitch for connecting the motor to its source of supply over the 1st and4th range portions and for establishing the dynamic braking circuit overthe 2nd and 3rd range portions.

2. A split-phase motor having quadrature displaced main and startwindings, a condenser in series with the starting winding, speedresponsive means for opening the starting winding circuit as the motorcomes up to speed, a source of supply for the motor, a reversing switchfor the main winding, another switch Ior alternately connecting saidmotor to its source of supply and'connecting the main and startingwindings in series with the condenser in a dynamic braking circuitindependently of the speed responsive means, and means for coordinatingthe operation of said switches movable in opposite directhe.

tions over a range of movement divided into 1st, 2nd, 3rd, and amconsecutive operating range portions, said means positioning saidreversing switch for one direction of motor operation over the let and2nd range portions, and for the opposite direction of .motor operationover the 3rd and 4th range portions and positioning said other switchfor connecting said motor to its source of supply over the 1st and 4thrange portions and for connecting the motor windings and condenser inseries in the'dynamic braking circuit over the 2nd and 3rd rangeportions.

3. A split-phase motor having quadrature displaced main and startwindings, a condenser permanently connected in series relation with thestart winding, speedresponsive circuit control means for opening thestarting winding circuit as the motor comes up to speed, a two-pole snapaction reversing switch for the main winding, line terminals, one lineterminal being connected to one end of the start winding and to'one poleof said reversing switch, another snap action switch having a 1stposition where it connects the other line terminal to the other pole ofthe reversing switch and to the starting winding circuit through saidspeed responsive circuit control means when the latter is closed, and a2nd position where the main and start windings are connected in serieswith the condenser through the reversing switch independently of thespeed responsive circuit control means, and operating means for saidswitches movable in opposite directions over a range of movement suchthat in one extreme position the motor is connected for one direction ofrotation and in moving to the other extreme position the switches areoperated in the following order, said other snap action switch is movedfrom the 1st position to the second position, the reversing switch isoperated to reverse the main winding,.and finally said other snap actionswitch is moved from said second position to said first position.

4. A split-phase motor having quadrature dislaced main and startwindings, a condenser permanently connected in series relation with thestart winding, speed responsive circuit control means ior opening thestarting winding circuit as the motor comes up to speed, a source ofsingle-phase supply, manually operated switching means and connectionsbetween said switching means, source of supply, and motonsaid manuallyoperated switching means including a snap action reversing switch forthe main winding,

and having a reversible range of movement in which movement'in onedirection over its range changes the motor connections from those foroperating the motor from the source of supply in one direction ofrotation, 1st to a dynamic braking connection with the main and startwindings connected in series with the condenser independently of thespeed responsive switch and with the connection to the source of supplyinterrupted,

2nd the same connection but with the main winding reversed, and finallyto connections for operating the motor in the reverse direction oioperation from the source of supply.

WILBUR W. WARNER.

